Individual projects' .adoc files can no longer eat the next section

Adding a blank line between include commands as a defensive measure
makes it much harder to cause this common error.

Change-Id: I2e02a4a1e0c4d5918329221f6b8575057ac463e5
Signed-off-by: Colin Dixon <colin@colindixon.com>
Merge "Individual projects' .adoc files can no longer eat the next section"